/*
 [auto_generated]
 boost/numeric/odeint/stepper/explicit_generic_rk.hpp

 [begin_description]
 Implementation of the generic Runge-Kutta steppers. This is the base class for many Runge-Kutta
 steppers.
 [end_description]

 Copyright 2009-2011 Karsten Ahnert
 Copyright 2009-2011 Mario Mulansky

 Distributed under the Boost Software License, Version 1.0.
 (See accompanying file LICENSE_1_0.txt or
 copy at http://www.boost.org/LICENSE_1_0.txt)
 */

#ifndef BOOST_NUMERIC_ODEINT_STEPPER_EXPLICIT_GENERIC_RK_HPP_INCLUDED
#define BOOST_NUMERIC_ODEINT_STEPPER_EXPLICIT_GENERIC_RK_HPP_INCLUDED

#include <boost/array.hpp>

#include <boost/numeric/odeint/stepper/base/explicit_stepper_base.hpp>
#include <boost/numeric/odeint/algebra/range_algebra.hpp>
#include <boost/numeric/odeint/algebra/default_operations.hpp>
#include <boost/numeric/odeint/stepper/detail/generic_rk_algorithm.hpp>

#include <boost/numeric/odeint/util/state_wrapper.hpp>
#include <boost/numeric/odeint/util/is_resizeable.hpp>
#include <boost/numeric/odeint/util/resizer.hpp>

namespace boost {
namespace numeric {
namespace odeint {

// forward declarations

#ifndef DOXYGEN_SKIP
template <size_t StageCount, size_t Order, class State, class Value = double, class Deriv = State,
          class Time = Value, class Algebra = range_algebra, class Operations = default_operations,
          class Resizer = initially_resizer>
class explicit_generic_rk;

struct stage_vector;

template <class T, class Constant>
struct array_wrapper {
  typedef const typename boost::array<T, Constant::value> type;
};

template <class T, size_t i>
struct stage {
  T c;
  boost::array<T, i> a;
};

template <class T, class Constant>
struct stage_wrapper {
  typedef stage<T, Constant::value> type;
};
#endif

template <size_t StageCount, size_t Order, class State, class Value, class Deriv, class Time,
          class Algebra, class Operations, class Resizer>
#ifndef DOXYGEN_SKIP
class explicit_generic_rk
    : public explicit_stepper_base<explicit_generic_rk<StageCount, Order, State, Value, Deriv, Time,
                                                       Algebra, Operations, Resizer>,
                                   Order, State, Value, Deriv, Time, Algebra, Operations, Resizer>
#else
class explicit_generic_rk : public explicit_stepper_base
#endif
{

public:
#ifndef DOXYGEN_SKIP
  typedef explicit_stepper_base<
      explicit_generic_rk<StageCount, Order, State, Value, Deriv, Time, Algebra, Operations, Resizer>,
      Order, State, Value, Deriv, Time, Algebra, Operations, Resizer>
      stepper_base_type;
#else
  typedef explicit_stepper_base<...> stepper_base_type;
#endif

  typedef typename stepper_base_type::state_type state_type;
  typedef typename stepper_base_type::wrapped_state_type wrapped_state_type;
  typedef typename stepper_base_type::value_type value_type;
  typedef typename stepper_base_type::deriv_type deriv_type;
  typedef typename stepper_base_type::wrapped_deriv_type wrapped_deriv_type;
  typedef typename stepper_base_type::time_type time_type;
  typedef typename stepper_base_type::algebra_type algebra_type;
  typedef typename stepper_base_type::operations_type operations_type;
  typedef typename stepper_base_type::resizer_type resizer_type;

#ifndef DOXYGEN_SKIP
  typedef explicit_generic_rk<StageCount, Order, State, Value, Deriv, Time, Algebra, Operations, Resizer>
      stepper_type;
#endif

  typedef detail::generic_rk_algorithm<StageCount, Value, Algebra, Operations> rk_algorithm_type;

  typedef typename rk_algorithm_type::coef_a_type coef_a_type;
  typedef typename rk_algorithm_type::coef_b_type coef_b_type;
  typedef typename rk_algorithm_type::coef_c_type coef_c_type;

#ifndef DOXYGEN_SKIP
  static const size_t stage_count = StageCount;
#endif

public:
  explicit_generic_rk(const coef_a_type& a, const coef_b_type& b, const coef_c_type& c,
                      const algebra_type& algebra = algebra_type())
    : stepper_base_type(algebra), m_rk_algorithm(a, b, c) {
  }

  template <class System, class StateIn, class DerivIn, class StateOut>
  void do_step_impl(System system, const StateIn& in, const DerivIn& dxdt, time_type t, StateOut& out,
                    time_type dt) {
    m_resizer.adjust_size(
        in, detail::bind(&stepper_type::template resize_impl<StateIn>, detail::ref(*this), detail::_1));

    // actual calculation done in generic_rk.hpp
    m_rk_algorithm.do_step(stepper_base_type::m_algebra, system, in, dxdt, t, out, dt, m_x_tmp.m_v, m_F);
  }

  template <class StateIn>
  void adjust_size(const StateIn& x) {
    resize_impl(x);
    stepper_base_type::adjust_size(x);
  }

private:
  template <class StateIn>
  bool resize_impl(const StateIn& x) {
    bool resized(false);
    resized |= adjust_size_by_resizeability(m_x_tmp, x, typename is_resizeable<state_type>::type());
    for (size_t i = 0; i < StageCount - 1; ++i) {
      resized |= adjust_size_by_resizeability(m_F[i], x, typename is_resizeable<deriv_type>::type());
    }
    return resized;
  }

  rk_algorithm_type m_rk_algorithm;

  resizer_type m_resizer;

  wrapped_state_type m_x_tmp;
  wrapped_deriv_type m_F[StageCount - 1];
};

/*********** DOXYGEN *************/

/**
 * \class explicit_generic_rk
 * \brief A generic implementation of explicit Runge-Kutta algorithms. This class is as a base class
 * for all explicit Runge-Kutta steppers.
 *
 * This class implements the explicit Runge-Kutta algorithms without error estimation in a generic way.
 * The Butcher tableau is passed to the stepper which constructs the stepper scheme with the help of a
 * template-metaprogramming algorithm. ToDo : Add example!
 *
 * This class derives explicit_stepper_base which provides the stepper interface.
 *
 * \tparam StageCount The number of stages of the Runge-Kutta algorithm.
 * \tparam Order The order of the stepper.
 * \tparam State The type representing the state of the ODE.
 * \tparam Value The floating point type which is used in the computations.
 * \tparam Time The type representing the independent variable - the time - of the ODE.
 * \tparam Algebra The algebra type.
 * \tparam Operations The operations type.
 * \tparam Resizer The resizer policy type.
 */

/**
 * \fn explicit_generic_rk::explicit_generic_rk( const coef_a_type &a , const coef_b_type &b , const
 * coef_c_type &c , const algebra_type &algebra )
 * \brief Constructs the explicit_generic_rk class. See examples section for details on the coefficients.
 * \param a Triangular matrix of parameters b in the Butcher tableau.
 * \param b Last row of the butcher tableau.
 * \param c Parameters to calculate the time points in the Butcher tableau.
 * \param algebra A copy of algebra is made and stored inside explicit_stepper_base.
 */

/**
 * \fn explicit_generic_rk::do_step_impl( System system , const StateIn &in , const DerivIn &dxdt ,
 * time_type t , StateOut &out , time_type dt )
 * \brief This method performs one step. The derivative `dxdt` of `in` at the time `t` is passed to the
 * method.
 * The result is updated out of place, hence the input is in `in` and the output in `out`.
 * Access to this step functionality is provided by explicit_stepper_base and
 * `do_step_impl` should not be called directly.
 *
 * \param system The system function to solve, hence the r.h.s. of the ODE. It must fulfill the
 *               Simple System concept.
 * \param in The state of the ODE which should be solved. in is not modified in this method
 * \param dxdt The derivative of x at t.
 * \param t The value of the time, at which the step should be performed.
 * \param out The result of the step is written in out.
 * \param dt The step size.
 */

/**
 * \fn explicit_generic_rk::adjust_size( const StateIn &x )
 * \brief Adjust the size of all temporaries in the stepper manually.
 * \param x A state from which the size of the temporaries to be resized is deduced.
 */
}
}
}
#endif  // BOOST_NUMERIC_ODEINT_STEPPER_EXPLICIT_GENERIC_RK_HPP_INCLUDED
